Process of flashing clay products and the product



April 28, 1931. F, K. P LL-QQCE 1,802,776

PROCESS OF FLASHING CLAY PRODUCTS AND THE PRODUCT Filed Dec; 27, 1927Fig.2.

Zmvcntor FORREST K.PENOE Gttorucgs Patented Apr. 28, 1931 iiaaanaFDR-REST K. FENCE, OF PADUGAH, KENTUCKY PROCESS OF FLASHING CLAYPRODUCTS AND THE PRODUCT Application filed December 2 This inventionrelates to the manufacture of flashed or colored unglazed clayproclucts, as for example, tilin for floors, Walls or other structureswhere decorative effects it! are desired. Flashed ware has heretoforebeen manufactured by placing it in the open space of the kiln andgenerating the reducing gases in the firing chamber of the kiln, saidgases coming in contact with the ware to efiectl 1 reduction therein ofthe coloring oxides, for example, oxide of iron, contained in the clay.The process as hitherto conducted is diiiicult of control, the resultsoften being uncertain, incomplete and unsatisfactory.

The object of the present invention is to make it possible to controlthe process of flashing and produce general or special eii'ects in theware as regards the coloring, as may be desired, of the ware, and tobring about large 20 economy in the manufacture of such ware.

The invention is embodied as herein set forth, the features of noveltybeing pointed out in the claims.

In the accompanying drawing Figure 1 illustrates an ordinary kiln havingsaggers or ware containers therein.

Fig. 2 is a vertical section on a larger scale of a container or saggershowing the ware, the

educing agent and sand therein.

In carryin out my process the tile or ware 7 is inclosed in the clay orother refractory containers, as at 5, along with the reducing agent 9,and an inert material 8, as for example, sand. The reducing agentspreferably consists of pulverized coal or coal slack but it can consistof any material having a suitable aflinity for oxygen when subjected toordinary kiln heat. The inert material preferably consists of sand andis used to dilute or cover the reducing agent and to wholly or partiallycover and surround the ware, such sand having the eifect of confiningand retarding the operation of the reducing agent. The reducing agentand diluent are preferably put into the container in alternate layerssurrounding the ware as illustrated in Fig. 2. By partially covering theware considerable and interesting variations in the coloring elfect canbe produced in the ware. Color effects can also be varied by includingin the 7, 1827. Serial No. 242,627.

container along with the reducing agent a suitable mineral, salt (NaCl)for example, or minerals that vaporize and under the conditions of thediluent of inert material. The saltwill impart a grayish tint. The container itself can be made of a material consisting of or containing areducing agent, graphite for example, to produce a flashing.

In the drawing Fig. 1 illustrates, in vertical section, an ordinary kilnin which the container 5 for the ware, the coal and sand are stacked intiers, the bottom of the container constituting the cover for the openend of the container next below, and the uppermost, one having a specialcover 5, if desired. The containers can be Wholly or partially sealedand the containers fired in the kiln in accordance with regular firingpractice. The kiln has an ordinary damper 6 in its out let by means ofwhich the draft can be controlled.

The advantages of the process are that definite results can be obtainedby the use of measured quantities of reducing agent and diluent inparticular contact with the ware, and striking and unusual color effectscan be obtained due to the confining of the ware and the reducing agentand diluent in a relatively small container. There is also great economyin handling, especially when the pieces are small, and a small quantityof reducing agent suflicies because it is confined and not widely and\vastefully diffused as in. ordinary practice. The inert material can berepeatedly used. fare to be treated with my invention can be fired inthe kiln with other non-reduced .vare, this being impos sible in theopen kiln process formerly used.

What I claim is 1. The process of manufacturing flashed unglazed clayarticles containing oxides, said process consisting in confining saidarticles in a refractory container along with an oxide reducing agentand a diluent pulverized refractory mineral and subjecting saidcontainer to a firing action in a kiln and thereby liberating the gasesof the reducing agent.

2. The process of manufacturing flashed unglazed clay articlesconsisting in confining said articles, an oxide reducing agent and asalt in a refractory container and subjecting said container to a.firing action in a kiln and thereby liberating the gases of the reducingagent.

3. A flashed unglazed clay article characterized by the fact thatportions of the flashed surfaces contain less than others of the normalcoloring oxides of said article.

4. A flashed unglazed clay' article characterized by the fact that theflashed surface contains less than the normal coloring oxide of saidarticle.

5. The process of manufacturing a flashed unglazed clay articleconsisting in placing said article in a container in juxtaposition to anoxide reducing agent and a pulverized refractory material adapted todilute the oxide reducing agent, and then subjecting said container andits contents to the firing action of a kiln.

FORREST K. PENCE.

